This month issue of Popular Photography the Canon 20D beats all
others in the sub $2,000 range. If Nikon can top the 20D then Canon
will have to answer back.

That may reflect to a slight extent on price, and perhaps actual release date, but putting out a new camera--even a slight upgrade--is at least a multi-year iteration from the time requirements are set in Jello to the time the camera is shipped.

I suspect Canon is at least tooling for the prototypes of the next version of the xxD, and the requirements for the version after that are at least in Jello.